Okay...after finally finding the right frosting at Sams, the whipped topping one, Rich's Bettercream...I bought the tub and put the whole thing in my freezer. Okay...now what? How do i unfreeze it, color it, work with it, really...has anyone used it?

You should find your answers here....
http://cakecentral.com/modules.php?name=Forums&file=viewtopic&t=601193&postdays=0&postorder=asc&&start=0

you'll find oodles of topics on the specifics too...

big bucket in freezer. remove only what you need for your project. Allow to thaw in refrigerator overnight. color just as you would other icing....BUT...be careful not to overmix or allow it to warm up...it'll turn into a Floam-like substance. Add stuff to it for fillings like...caramel, whipped cream cheese, peanut butter and a bit of powdered sugar.

Search in the forums for more info.

The link above gives you some great tips for doctoring liquid Bettercreme. I did not read all of the pages, just the first few. When I buy the tub from Sam's it is pre-whipped. Sometimes I store the entire bucket in my freezer, taking out just the amount that I need and placing it in the refrigerator several hours before using it. When I don't have room for the entire buck, I put it in smaller containers and freeze the containers. When I need the icing, I pull out a container, place it in the refrigerator several hours before use.